Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 4)
4.
A is thrice as good as workman as B and therefore is able to finish a job in 60 days less than B. Working together, they can do it in:
Answer: Option
Explanation:
Ratio of times taken by A and B = 1 : 3.
The time difference is (3 - 1) 2 days while B take 3 days and A takes 1 day.
If difference of time is 2 days, B takes 3 days.
| If difference of time is 60 days, B takes |  |
3 | x 60 |  |
= 90 days. |
| 2 |
So, A takes 30 days to do the work.
| A's 1 day's work = | 1 |
| 30 |
| B's 1 day's work = | 1 |
| 90 |
| (A + B)'s 1 day's work = | |
1 | + | 1 | |
= | 4 | = | 2 |
| 30 | 90 | 90 | 45 |
 A and B together can do the work in |
45 | = 22 | 1 | days. |
| 2 | 2 |
Discussion:
287 comments Page 29 of 29.
Sanky said:
5 years ago
A:B = 1:3.
B = 3A.
Difference is 60days,
therefore B - A = 60,
3A - A = 60,
2A = 60,
A = 30 & thus B = 90.
Now, 1/30 + 1/90 = 22.5.
B = 3A.
Difference is 60days,
therefore B - A = 60,
3A - A = 60,
2A = 60,
A = 30 & thus B = 90.
Now, 1/30 + 1/90 = 22.5.
Ranjana shree said:
5 years ago
We can simplify it.
Assume if B worked for 90 days and;
C worked for 30 days.
B's 1-day work = 1/90.
A's 1-day work = 1/30.
A + B = 4/90 work.
ie, 90/4 = 22.5.
Assume if B worked for 90 days and;
C worked for 30 days.
B's 1-day work = 1/90.
A's 1-day work = 1/30.
A + B = 4/90 work.
ie, 90/4 = 22.5.
Paru said:
5 years ago
@Harsha
You gave a very good explanation, thank you.
You gave a very good explanation, thank you.
Ahamed said:
5 years ago
Thank you all for explaining.
Adheer said:
5 years ago
If B completes the work in X days, then A completes the work in X-60 days.
A is thrice good as workman as B then, the ratio of the time taken to finish the same work is 1:3
Then,
(X-60) : X :: 1 : 3
Solving this, X = 90
Means B finish the work in 90 days and A finishes the work in 30 Days,
Working together, their 1-day work,
1/90 + 1/30 = 4/90 = 2/45.
Mean working together, they finish the work in 45/2 = 22(1/2) days.
A is thrice good as workman as B then, the ratio of the time taken to finish the same work is 1:3
Then,
(X-60) : X :: 1 : 3
Solving this, X = 90
Means B finish the work in 90 days and A finishes the work in 30 Days,
Working together, their 1-day work,
1/90 + 1/30 = 4/90 = 2/45.
Mean working together, they finish the work in 45/2 = 22(1/2) days.
Srikanth said:
5 years ago
Thanks @Sundhar.
Vishakha said:
4 days ago
According to me, it is 20 days.
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